Good Sleep, Happy Life

What is Visco (Memory Foam)?

It is an open-cell and intelligent material that responds to individual needs thanks to the mobility capability of its molecules. Its most characteristic feature is recognized by its gradual recovery following compression from pressure and/or heat. When a heavy object (for example, the human body) is placed on viscoelastic sponge, the sponge gradually takes on the shape of the object, and after the weight is removed, the sponge slowly returns to its original shape. Due to this gradual recovery, viscoelastic sponge can also be described as "slow-recovery" sponge. [1]

Entry into Our Lives

Did you know that viscoelastic foams, also known as polyurethane memory foams, were first developed by NASA? They were developed by the AMES research group in the 1960s for use in spacecraft seats to reduce the extreme pressure that astronauts experience during launch and landing. Later, it was used as a shock absorber inside the helmets of American football players, and due to its pressure-reducing properties, it became an unparalleled solution for the beds of bedridden patients and became widespread. By reducing pressure in areas in contact with the bed, relieving capillary blood circulation in these regions, and even preventing blood circulation blockages, it provided unique therapeutic benefits. [2]

Figure 1. Polyurethane production [1]

Figure 2. Entry of viscoelastic foams into our lives [3]

Viscoelastic polyurethane foam, called smart foam, is used today in pillows and mattresses thanks to advancing technology and provides us with the opportunity for perfect sleep. Visco is a product with the ability to take shape through body heat and pressure. For example, when you place your head on a pillow containing visco foam, the pillow takes on a shape that wraps around your head and provides equal pressure distribution to every point of contact. This elasticity and comfort is ideal for quality sleep.

Figure 3. Viscoelastic mattress conforming to body shape [4]

Viscoelastic systems are fundamentally obtained by polyurethane chains with high mobility creating a homogeneous cell structure. Visco foams are divided into two types: Pneumatic (Physical Visco pVE) and Chemical Visco (cVE).

Figure 4. Foam cell and operating principle of visco foams [6]

In Physical Visco foams, the visco effect stems from their closed-pore structure and physical properties. It is independent of ambient temperature. It has a permanent hand feel and recovery times proportional to the size of their cells. Cell size directly affects the time it takes for air to pass more or less easily and return to the original state. [5-10]

Figure 5. Operating principle of chemical visco foams [10]

In chemical visco systems, the visco effect stems entirely from the glass transition temperature of the material, that is, from its chemical properties. It is dependent on ambient temperature. Tg temperature is the temperature at which the rigid structure of polymer chains softens and becomes able to move. Polymeric chains in visco products can move in a limited way at room temperature. As a result of this limited movement, the time to return to the original state after compression is longer compared to conventional HR foams. Its open-pore structure allows the foam to breathe and moisture to disperse. Kimteks Polyurethane Composite Polymer Technology exhibits more effective viscoelastic properties and nothing can replace its structural characteristics. With its well-distributed pore structure, it provides permanent hand feel and comfort, and allows the foam to breathe. [11,12] As the Kimteks Polyurethane family, we offer "Next Generation Viscoelastic Systems" developed using Composite Polymer Technology that provide advantages to manufacturers before and after application, based on MDI. In particular, with adjustable product properties, KimVISCO using its own composite cell structure is a viscoelastic system that ranges from very soft to firm foam, combines pneumatic and chemical properties in a single body, and expands the application possibilities of memory foams. With creaming/rise time of 13 seconds and stringiness/gelling time of 63 seconds, this versatile viscoelastic foam is suitable for the production of pillows, cushions, mattresses, orthopedic products, insoles and many other applications.   Emre Aytan Research and Development Manager Kimteks Poliüretan San. ve Tic. A.Ş.  

References 1. Aastha S.Dutta Recycling of Polyurethane Foams Plastics Design Library 2018, Pages 17-27 https://doi.org/10.1016/B978-0-323-51133-9.00002-4 2. Kaoru Aou, Alan K. Schrock, Daniel Baugh III, Rogelio R. Gamboa, Linda C. Ulmer Viscoelastic recovery behavior and imperfection in reactive polymer network of viscoelastic polyurethane memory foams Polymer 117 (2017) 183-197 3. https://www.amerisleep.com.au/how-to-make-a-memory-foam-mattress.html 4. https://mattresszine.com/memory-foam-mattress/novosbed-harmony-memory-foam-gel-mattress/ (http://i43.tinypic.com/2wekwuc.png) 5. R. Landers, R. Hubel, R. Borgogelli, "The Importance of Cell Structure for Viscoelastic Foams", Conference Proceedings, Polyurethanes 2007, September 24-26, 2007, Orlando, Florida 6. Kaoru Aou*, Shouren Ge, Daniel M. Mowery, Robert C. Zeigler, Rogelio R. Gamboa Two-domain morphology in viscoelastic polyurethane foams Polymer 56 (2015) 37e45 7. Bernard E. Obi Polymeric Foams Structure-Property-Performance A Design Guide 2018, Pages 299-331 8. H. Nurul 'Ain, T. I. Tuan Noor Maznee, M. N. Norhayati, M. A. Mohd Noor, S. Adnan, P. P. Kosheela, Devi, S. Mohd Norhisham, S. K. Yeong, A. H. Hazimah, Irma Campara, Vahid Sendijarevic, Ibrahim Sendijarevic Natural Palm Olein Polyol as a Replacement for Polyether Polyols in Viscoelastic Polyurethane Foam J Am Oil Chem Soc DOI 10.1007/s11746-016-2832-7 9. Viscoelastic Foams, Urethanes Technology, vol. 18, no. 6, December 2001/ January 2002, p.22 10. Michael Krebs Roland Hubel Highly Sophisticated Cell Opener for Viscoelastic Foam 11. N.N., "Examing viscoelastic flexible polyurethane foam", INTOUCH, Regular publication of the Polyurethane Foam Association, Vol. 11(1), 2003 12. US 9266996 B2 B.E. Obi, A.K. Schrock, R.R. Gamboa, M.A. Shafi, K. Aou, Cellular Structures and Viscoelastic Polyurethane Foams, Dow Global Technologies LLC, published, 2010-01-21, http://patents.google.com/patents/US9266996B2.